dalton's atomic theory



We explain what Dalton's Atomic Theory is, the atomic model that he proposes, and its importance. Also, who was John Dalton.

Dalton discovered that all matter is made up of a limited number of atoms.

What is Dalton's Atomic Theory?

It is known as the Dalton's atomic theory or the Dalton atomic model to the first model of scientific bases regarding the fundamental structure of matter. It was postulated between 1803 and 1807 by the British naturalist, chemist and mathematician John Dalton (1766-1844), under the name of "Atomic Theory" or "Atomic Postulates".

This model proposed a scientifically plausible explanation for most of the enigmas of the chemistry 18th and 19th century. It postulates that all matter of the world is composed of atoms, that is to say, that there is a finite number of fundamental particles.

In addition, he argues that simply from the combination of these particles all the structures complex of matter. The direct ancestor were the Greeks of classical antiquity.

The postulates of this model are:

  • Matter is made up of minimal, indestructible and indivisible particles called atoms.
  • The atoms of the same element are always identical to each other, with the same mass and the same properties. Instead, atoms of different elements have masses and different properties.
  • Atoms do not divide and cannot be created or destroyed during chemical reactions.
  • Atoms of different elements can combine to form compounds in different proportions and amounts.
  • When they combine to form compounds, the atoms are arranged according to simple relationships, described by integer numbers.

Despite the obvious importance of the Dalton Atomic Model in the emergence of modern chemistry, it should be noted that this theory has many shortcomings, as noted later.

For example, Dalton thought that gases were monatomic substances, and that gases molecules were always composed from the minor proportion possible. This led him to suppose that the Water It was composed of a hydrogen atom and an oxygen atom (HO) and to miscalculate the atomic weight of many compounds.

Importance of Dalton's Atomic Theory

The model held that atoms combined to form different substances.

Although it was not the definitive one in the history of chemistry, Dalton proposed the first, foundational model for chemistry. It allowed solving questions on the matter that had no answer in his time.

For example, he explained the cause of fixed stoichiometric ratios in chemical reactions, that is, why compounds are formed according to fixed amounts of each atom during a reaction.

The ability to test many of Dalton's postulates laid the foundation for future chemistry. Many of his errors remained unsolved until the nineteenth century, when, for example, the first evidence appeared that atoms, contrary to Dalton's assumption, were divisible.

The great advantage of this model was to scientifically explain an immense set of complex and diverse compound facts from a fairly simple combinatorial theory.

John Dalton Biography

John Dalton lived in England, between 1766 and 1844.

John Dalton was born in Cumberland, England, on September 6, 1766, the son of British Quakers (members of a church of Christian origin called the "Church of Friends"). Its facilities with the math They were evident from an early age, but his parents' religion prevented him from making his way to a university, so he had to be educated at the "New School" for religious dissidents that he opened in Manchester.

In that institution he was professor of Math and Natural Philosophy. Later he was elected a member of the Manchester Literary and Philosophical Society, where he presented his first works. Among other findings, he discovered color blindness (named in his honor), a visual disease that he suffered and that consists of the inability to identify the colors.

Among his other important theoretical formulations are the Gas Law, the Atomic Model, and numerous scientific classifications of plants. He finally died on July 27, 1844. One of the craters of the Moon bears his name in eternal homage.

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